Broken souls in the Underground
by MonkeyGirl13
Summary: Rosa never had a good life for many years but can the monsters help her? or will nothing heal her? Bad summery but please read and reveiw
1. Chapter 1

**I do not own Undertale OC. Also this is the pacafist run but with my OC and some other chapters.**

Falling is never fun, wether it's tripping and falling on your knees, to falling down a hole into the home of the monsters. Oh sorry you must be confused on what is happening. Let me start from the beginning my name is Rosa I am 16 years old and I have black hair with a red streak going through the frindge and my hair was cut in a pixie cut my eyes a sparkling blue. I was wearing torn blue denim shorts with black ripped leggings I also wore a floaty red top with a black leather jacket. I was much thinner and smaller than most other girls for my age the main reason for this is because I have lived on the streets since I was 5 years old. Now before you all 'awww' or think I need sympathy well I don't I survived 11 years without any sympathy I don't need to start now. Anyway my mum died when I was born but my dad loved me for the both of them. That was until my 5th birthday my dad had ordered me a gift but because the mail men couldn't deliver it he had to collect it. He left me alone for an hour and that's how long it took for him to be ripped out of my life. The police gave me his present, which was my leather jacket that I was always begging to get. I never took it off.

After my father died I didn't want to go into the orphanages so I decided to live on the streets, they were rough. I was always scared of the people on the streets but then I grew up and taught myself how to fight when it was nessasary. Then when I turned 15 I met Jake. Jake was a street thug who was a leader of a gang. At first thinking I was a man he wanted to mug me but as soon as my hair fell down he stopped and the flirting began. I dated him but he was no prince charming he called me horrible names and he began to hit me when I angered him. I grew fearafull of him so much I ran away towards Mt. Ebbot. That was how I was now falling.

I suddenly came into contact with the hard floor sitting up I rubbed my sore arms I could feel tears beginning to well up when I heard a voice speak up to me.

"Howdy I'm Flowey, Flowey the flower" I looked around me and saw a yellow flower with a smiling face. "Golly that's quite a fall that you just took I hope that your alright" I smiled slightly at the niceness in this flower. "Since there is no one around I guess little ol' me will have to teach you how things work down here" Suddenly several white pellets appeard around. "These are called 'Friendliness pellets' catch them and your soul will grow stronger" He threw them at my direction I allowed them to hit me. Suddenly a horrible stabbing pain hit me like a thousend knives I fell to my knees. "Hahahaha you idiot in this world it's kill or be killed" I was surronded by the pellets that began to enclose. " _DIE!_ " When I thought that I was gonna die Flowey was hit away by a fireball looking back up I saw a large goat monster. From the features I could tell that this was a woman she was wearing a long purple dress.

"That horrible miserable creature torturing such a poor innocent youth" She looked at me and smiled gently. "Do not worry my child my name is Toriel caretaker of the ruins" ' **My child** '? She called me her child but maybe that's what she calls all of the fallen humans. "come with me I shall teach you how to survive in the ruins" After several rooms of doing puzzles Toriel turned to me. "My child I must leave you for a few minutes. I am sure you wil be fine seeing as you are much older than most of the fallen humans. But please take this in case you should need me" She then gave me a small old fashioned phone. After waiting for a few minutes I decided to walk ahead and after meeting a few monsters which I befriended I found a room with a large black dead tree suddenly my phone began to ring. Looking up I saw Toriel ringing me I smiled at her and when she saw me she looked worried. "My child there you are I was just on my way to collect you for I have a surprise for you" she gently took my hand which shocked me I have not had someone this nice in my life in years. But as she lead me to a small house I smiled at the cuteness of the house. Leading me inside I noticed that it was nicely furnished and when I stood in the entrance an amazing smell hit me the smell was cinnimon. My stomach rumbled slightly at the smell rembering that the last time I ate was in a week. But Toriel then lead me to a different room we stood in front of the door. "This will be your room my child" I felt her gently stroke my hair as a mother would do to their own, it felt nice, comforting. She then left me to explore my new room. Looking 'round I saw that the room had mulitple clothes but nothing that I would wear through choice. Then I saw the bed laying down on it, it felt like a large cloud compared to the cement floor. I fell asleep as soon as my head hit the incredibly soft pillow.

I awoke a few hours later looking around I noticed that the light had been turned off, which meant that Toriel had been in the room. I slid off the bed and noticed a plate on the floor on the plate was a slice of butterscotch pie. I licked my lips but I decided to eat a bit and save the rest for later. After I had placed my pie away I went to the living room where I saw Toriel sitting in a large chair reading a book.

"Ah I was wondering when you would be waking up my child" I smiled but then a thought came to my mind.

"hey Toriel how do I exit the ruins?" She seemed to get nervous when I asked that question.

"what do you mean? You do not need to leave the ruins" I persisted.

"but how would I exit if I wanted to" Toriel stood up.

"excuse me my child I need to attend to something" With that she left I decided to follow her to basement where I found her standing in a hallway. "So you wish to know how to return to your home? At the end of the hallway is the exit of the Ruins I am going to destroy it. Now be a good child and return to your room" I shuck my head and followed after her. "You fool if you leave they Asgore will kill you please go back up" Again I followed her to find her at a large door. "you want to leave so badly prove to me you have the strength to survive" Suddenly Toriel threw a large fireball at my direction.

"I won't fight you Toriel!" I yelled at her but she kept attacking, on her 5th attack I felt a burning feeling in myside. Again and again I refused to fight when suddenly she let out a sad chuckle.

"It's pathetic isn't it? I cannot even protect one human child" I felt tears began to prick my eyes. Toriel sighed. "If you truly wish to leave then I shall not stop you. But please if you leave do not return, I hope you understand." Toriel kneeled down and hugged me as I began to cry.I watched as she left I opened the door and walked into a large room where I saw Flowey.

"Hehehehe you think your so good, so what you spared the life of a few monsters, you'll kill eventually and when you do I'll be there believe me" he then let out ablood curdling laugh and left. I knew from there on this would be one hell of an adventure.


	2. Chapter 2

After I went through the long corridor and exited through another door I came to a large snowy forest. The cold hit me instantly making me shiver and my teeth chatter. I looked ahead and saw that in the distance was a bridge I decided I should head that way, trudging through the thick snow I came across a large stick a thought came into my head that I should take it for defense. But as soon as I tried to lift it my arms went dead from the weight, I set it down and walked on but only a few feet away I heard a loud cracking noise. Spinning around I saw that the large stick now laid in pieces smashed up as if someone had stomped on it a shiver went up my back and this time it wasn't the cold. I kept on going until I came to the large bridge when I heard the distinct sound of footsteps behind me, the crunching of the snow growing louder with every second. Every muscle in my body began to tense up as I became unable to do to anything. I suddenly felt the presence of something or someone standing right behind me when all of a sudden a Broklyn accent spoke up.

"Human, don't you know how to greet a new pal? Turn around and shake my hand" I shivered from fear as I turned around to see a shadowed figure with their arm outstreched. Hesitently I grabbed their hand and prepared to shake when I heard a sound emmit from the stranger, which seemed to be trumping. I began to blush as the reality hit me it was a whoppie cushion hidden in the stranger's hand. I then began to laugh as the strange came into the light. The feature's showed that it was a man he was slightly taller than me oh and he was a skeleton. He wore a thick light blue jacket with white fur on the hood, with a pair of dark blue shorts and a pair of white slippers. He turns to me and smiles almost laughing at his own jokes. "The ol' whoppie cushion in the hand trick. Works everytime" I cover my mouth with my hand as I began to giggle I swear that I saw a blue blush creep over his face for a second when it quickly disspaeared. "The name is Sans, Sans the Skeleton" I smiled.

"my name's Rosa" Sans smiled even more.

"That's a nice name" He then told me about how he was a sentry looking out for humans. "I'm not that much into hunting humans, my brother however is a human hunting fanatic. That's him over there, I know go over this bridge my bro made the gap to big to not stop anyone" We crossed over the bridge to what seemed to be a sentry station and a odd looking lamp. "Quickly hide behind that convenietly shaped lamp" I didn't think twice before running behind it and dusking. From where I was hiding I saw a tall skeleton appear, he was wearing a white outfit with a long red scarf.

"BROTHER WHAT ARE YOU DOING? YOU ARE SUPPOSED TO BE LOOKING FOR HUMANS" I wasn't ready for him to yell so I had to cover my ears. (A/N I AM CHANING THE STORY SLIGHTLY BUT IT'S JUST TO HELP THE STORY ALONG)

"looking at this lamp. Do you wanna look?" I became almost humored by this sure he was giving me away but the tall skeleton seemed like a young child.

"NO I NEED TO CAPTURE A HUMAN THEN I THE GREAT PAPYRUS WILL GET ALL OF THE RESPECT I DESERVE" I sighed and I realised that I actually felt sorry for this skeleton. So against my better judgement I came out of the hiding space so Papyrus could see me. "OH MY GOD A HUMAN! I WILL CAPTURE YOU! BUT PLEASE WE MUST FIGHT IN A BETTER PLACE MEET ME AT THE LAKE NEAR SNOWDIN" he then left I let out a sigh of realive.

"you know that was kinda dangerous" I looked to my side and saw Sans. "But it was kind to do that for my bro. Don't worry I'll walk you to Snowdin" with that we began to walk but as minutes went by the cold was getting to me. Sans noticed this and asked. "hey kiddo you cold?" I could only nod I heard unzipping and then a warmth was enclosed around me. I looked at my body and saw Sans' jacket on me I zipped it up and looked at Sans thankfully.

"thanks Sans" he nods.

"I can't let you fight my bro as a popsicle now can I?" I smile and we kept on walking hugging the jacket close to me we soon came to a small town with multiple houses. "Hey kid do you mind if I have my jacket back?" I blushed and quickly handed back his jacket. He took the jacket and smiled. "well don't worry kiddo I'll keep an eye socket out for ya" I smiled and walked away heading futher into town when I came to a clearing I felt the snow intensifie as the wind picked up. As the wind settled Rosa saw Papyrus standing in front of her.

"HALT HUMAN YOU SHALL NOT PASS WITHOUT FIGHTING ME! THE GREAT PAPYRUS!" Rosa looked wearily at Papyrus but stood straight when he summoned several large blue bones that fired at her. Rosa stood completly still as she felt the bones phase through her suddenly in front of her a small blue heart appeard. "NYHEHE HEH YOUR BLUE NOW" Suddenly multiple bones fired towards Rosa she dodged most of them but two of them managed to cut her face. For the last attack Papyrus sent a row of many bones towards Rosa, Rosa dodged to the side and managed to just get away from the attack. As the attack ended Papyrus looks away in sadness. "HOW CAN THIS BE I CAN NOT EVEN DEFEAT SOMEONE AS WEAK AS YOU. NOW I WILL NEVER BE ABLE TO CAPTURE A HUMAN AND THE NUMBER OF FRIENDS I HAVE WILL REMAIN STAGNENT" Rosa looked down in thought until she walked foreward a few feet standing behind Papyrus.

"hey you wanna be friends?" Papyrus spun 'round grabbing Rosa and hugging her close.

"OH THANK YOU HUMAN I WILL BE THE BEST FRIEND YOU HAVE EVER HAD" after Rosa hugged him back he placed her on the ground. "NOW AS YOUR FRIEND II WILL LET YOU PASS FROM HERE YOU MUST GO THROUGH WATERFALL AND HOTLAND TO GET TO THE KING. I AM SURE IF YOU ASK 'PLEASE MR DREEMUR MAY I LEAVE' I AM SURE HE WILL LET YOU LEAVE" He then added his number to Rosa's phone and left. Rosa smiled and walked towards Waterfall looking back once to catch a glimpse of a golden flower following her.


	3. Chapter 3

Rosa had walked for hours now after she had left Snowdin she had bumped into Sans as she walked through Waterfall she decided to remember that memory.

 _Rosa had just left Snowdin where she had thought_ _Papyrus when she noticed Sans was stood behind a stall of some kind. She decided to walk up to him smiling she asked him._

 _"Hey Sans. What's with the stall?" He smiled and answered._

 _"What you never seen a guy have more than one job before?" Rosa smiled at this because knowing Sans he seemed to lazy to be able to keep more than one job so she didn't know how he had more. "Well hey I'm about to go on my break so you wanna go to Grillby's?" Rosa thought for a moment before nodding. "Great, come on I know a shortcut" He grabbed her and pulled her along with him. At the sudden touch Rosa's heart skipped a beat and a deep blush creeped on her face and little did she know that Sans also had a blush on his face. A blinding flash made Rosa close her eyes tightly and when she opened them she saw that she was inside Grillby's. "Quick shortcut huh?" Rosa could only just nod almost in awe at how fast they did actually arrive at Grillby's. They both sat down at the bar on the tall stools but as Rosa sat down a loud familiar noise erupted out. Rosa felt a large blush creep acorss her face as Sans pulled out the whoppie cushion from under her. "careful some wiredo is placing these down. So what do you wanna eat?" Rosa looked at the menu carefully before chosing._

 _"I would like a burger please" Sans smiled._

 _"yeah that sounds nice, Grilbz two orders of the burg" Grillby nodded and walked into the kitchen to cook our order. That was when Sans turned to Rosa saying. "hey I need to ask you something. Have you ever heard of a talking flower?" Rosa's eyes widened, Sans knew about Flowey as well but just in case he didn't all she did was nod. "So you've heard of it to? The echo flower" a little bit of Rosa felt saddened that Sans didn't say about that evil little flower. "There scattered across the marsh they repeat the last thing they have heard over and over" He looked down and back saying. "I think someone is pranking my bro with one cause he says a flower will tell him predictions, compliments and other stuff" He looked worridly at me saying."keep an eye open will ya?" Rosa smiled and nodded reasuringly. At this point Grillby came out of the kitchen with two plates both having burgers on top of them. When he placed them down Sans passed Rosa some ketchup which she took but as she poured it the lid fell of an ketchup covered the burger. Rosa spluttered but ended up laughing loudly along with Sans. "Here have mine instead" He slid the plate over to Rosa and to her, which she did the same back making Sans blush a deeper blue then he's ever gone before. After eating Sans held his hand out to Rosa. "here I'll take ya back to my post" She grabbed his hand and was blinded yet again and as she opened her eyes she was outside Sans station. He walked behind his station smiling at Rosa before saying. "This was fun we should do it again" What happened next almost surpirsed Sans. Rosa giggled before saying._

 _"Yeah that would be really fun" Before going towards Waterfall._


	4. Chapter 4

**Hey guys you are gonna kill me but i am going to skip ahead in the story to the final fight in the castle with Flowey  
**

Rosa had been through all sorts that could only be described as hell she had to fight for her life against Undyne, do varies battles against Mettaton and even had to avoid becoming a dancing spiders next meal. After all of this she finally met the king of all the monsters and even after he forced her to fight him she refused to kill him. He was on his hands and knees and she spared him only for the little flower to kill him and take the human souls transforming into a large creature that Rosa had to fight. Luckily for her she had just survived the ordeal by the human souls coming to her rescue as Flowey was about to kill her. After which Rosa left the Underground she felt saddened that she would leave the monsters down their. Toriel, Papyrus, Alphys, Sans. As she looked at the sunset in front of her she slumped to her knees and began to cry as the thoght of leaving them forever set in her mind. But at that moment Flowey had popped up and told her that she had a special power he used to have. She could go back to before she had fought Asgore back when she had just delivered Undynes letter heck even after Alphys came out with the lab incident. Rosa didn't need to think twice before she did what Flowey told her and used her 'reset powers' and when she opened her eyes she was stood outside the barrier. As she went to enter she thought to herself. _'Flowey had better not be lying to me'._

Rosa walked in and saw Asgore just like before he pulled out his spear and prepared to make the first move when suddenly a heat filled the room. Just as the heat arrived Asgore was sent back by a fireball. Rosa gasped as she saw Toriel enter the room glaring at Asgore holding her hands out towards him. Rosa didn't care that she was just about to fight Asgore anymore she ran towards Toriel happy tears filled her eyes as she wrapped her arms around Toriel hugging her. Toriel chuckled softly and hugged her back.

"Do not worry my child it is I your friend Toriel" Toriel told Rosa that she believed that the fight between the two should be held off because no one should die for the freedom of the other, which Rosa was more than happy to agree to. As the fight had ended all of Rosa's friends had started to fill the room thinking they were preventing the fight. The last person to enter was Sans who just smiled saying.

"'sup" Rosa smiled and ran over and hugged him saying.

"So I guess I still haven't gained LV or EXP, huh?" Sans smiled hugging her back avoiding the gaze of his brother who was smiling slyly.

"ha guess so kiddo" Sans then stood next to his brother and Toriel who spoke.

"my child it would seem as if you must stay with us for a while. But looking at all these great friends you have made I do not think this will be such a bad thing" Rosa started getting happy tears in her eyes but suddenly a sharp pain struck her and the next thing she knew she was held up by a thorny vine as was all of her friends. Flowey popped up laughing.

"You idiot, you have learned nothing. In this world it's kill or be killed" Rosa managed to speak although the thorns were stabbing into her.

"Why are you still doing this?" Flowey laughed.

"You see if you finish the 'game' then you won't want to play me with me anymore. Tell you what if you do beat me then I'll give you your happy ending, I'll break down the barrier, I'll give back the souls and I'll let your friends go" His expression then went dark. "But that won't happen. You." He began to tightening the vine stabbing the throns deeper in. "I'll keep you here no matter what even if that means killing you 100,000,000 times" Suddenly Rosa was surrounded by the sharp pellets and the pellets repeatedly stabbed into Rosa's body. Rosa was now bloodied and in a great deal of pain but as the final round of pellets went towards her a large wall of fire destroyed the attack.

"Do not be afraid my child. For even if things look bleak we shall always to be here to protect you" After all of Rosa's friends protected her each time she felt her health returning. After this she had managed to escape from the vine and glared at Flowey as all of the monsters that she had met entered the room willing to protect her from Flowey. Suddenly Flowey began to laugh.

"You idiots all your souls are mine" A bright light blinded Rosa and made her cover her eyes with her sleeve. When the light dimmed a small goat child was stood there he was wearing a green and yellow striped jumper with a pair of black pants. He smiled at Rosa and said. "Chara, are you there? It's me your best friend Asreil Dreemur" In another bright light this Asreil was now as tall as Asgore with Toriel's dress on. He pulled out a large sword and swung at Rosa nearly hitting her again and again before he pulled out a large gun that continuously fired stars until it fired a large rainbow coloured ray. Rosa had dodged millions of attacks but could feel herself getting weaker and weaker. Soon after Asreil had showed another more powerful form she could now feel the weakness setting in and as a darkness was surrounding her making her start slumping. But then she sensed a strong pull from Asreil's soul as if the other souls were still resonating within him, standing up Rosa forced the souls out one by one. She had promised Toriel and Asgore that she would be with them forever and that she thought of them as parents, she then told Alphys that she wanted to watch Anime's with her and that she believed in her, she then lightly punched Undyne and asked Papyrus about cooking spaghetti. Then lastly she found Sans' soul. She had told him some skeleton puns expecting him to laugh but what he said made tears form in her eyes.

"Just give up I did" Rosa considered talking about his brothers but instead she walked up to him and hugged him whilst crying.

"please come back to me Sans I feel like you know me better than anyone. I already lost my father please don't let me lose you" Rosa suddenly felt a hand on her back she looked up and saw Sans looking at her smiling.

"Don't worry you wont" He hugged her back tightly and when she let go she found herself standing in front of Asreil and even though all of her friends were saved she could still feel a soul that wanted to be saved. I walk forward as Asreil starts going backwards.

"No! I don't need anyone! Leave me alone!" He suddenly fires a large beam of light but Rosa carried on until he sighed and stopped and started whimpering. "I'm so afraid Chara, I'm so alone Chara, I'm, I'm.." In a bright light Asreil had gone back to his child form he was crying and wiping his eyes. "I always was a cry baby wasn't I Chara" Rosa gave him a confused look. "I know your not Chara, Chara left ages ago" Rosa saw that he seemed more upset so she moved forward.

"My name is Rosa" He looked up and smiled.

"Rosa? That's a nice name. Look I know that you might not want to forgive me I've done so many bad things" Rosa smiled and walked up to him hugging him. "I don't want to let go" She hugged him and then let go as he broke down the barrier and as he walked away to leave Rosa's eyes began to tear up. "Oh and Rosa take care of mum and dad for me" He then walked away and in a moment she felt a dizzy spell and collapsed. Rosa awoke and saw all of her friends surrounding her and all together they walked to the surface where Toriel had asked what she would be doing and Rosa had asked if she could stay with Toriel. Toriel allowed her and said how if she wanted she would be her parent. When Rosa went home with Toriel she was taken up to her new room where she saw that she had a large bed and the room was painted white as Toriel said that she could paint it herself when she had settled in. Rosa couldn't be more happy she had a mother and a father, Toriel and Asgore, she was the ambassador to the monsters and she had a large group of friends. But something felt missing and after thinking about it for the entire day the thought hit Rosa. Flowey. She had always thought he was just an evil weed but after meeting Asreil she understood that he couldn't help feeling that way. So late at night when Toriel and Asgore had thought that Rosa was fast asleep she grabbed her coat and backpack and placed a plant pot, a trowel and a large piece of rope in the bag. She climbed out of the window and made her way to the entrance to the Underground. She tied the rope to a uprooted tree and made her way down when she saw Flowey looking upset she walked towards him when he said.

"Rosa? What are you doing here?" She pulled out the plant pot.

"I want you to come with me" Flowey scoffed.

"why cause you think you can make me feel something again? That won't happen" Rosa sighed.

"No because you are the only one who understands about the resets and everything I can't tell the others" Flowey seemed shocked.

"Well what about Smileytrashbag? You can talk to him about this stuff"

"No I can't there are somethings I can tell him but not everything. Please Flowey" Flowey sighed.

"Fine but you can't tell anyone that I'm really Asreil. I don't want them to see me like this" Rosa smiled and agreed before placing him in the plant pot and setting off home and placed him on the side drawer. When she fell asleep she didn't know this but Sans had teleported into her room to check on her when he saw Flowey.

"What are you doing here weed?"

"Rosa brought me here trashbag" He glared at Flowey but still went to Rosa making sure she was sleeping peacefully before turning to leave. "Hey Sans" This made Sans turn around surprised he wasn't called his nickname. "You better watch over Rosa and keep her safe"


End file.
